Stents manufactured for the purpose of preventing the additional progress of stenosed regions and facilitating the flow of materials within the human body through the extension of the diameters of various types of organs in the human body are each provided with specific characteristics by weaving wire, made of shape memory alloy or the like, to intersect itself according to a predetermined method.
Stents should be formed to be suitable for their purposes according to the sizes and characteristics of various types of organs and lumens and environments where the stents will be placed. For this purpose, methods for manufacturing a stent through the intersection of wire can propose various cell shapes and woven structures.
In particular, common methods for manufacturing a stent generally adopt a wire intersection method designed to perform weaving so that predetermined patterns are formed in the lengthwise or circumferential direction of a stent. For a prior art document regarding a conventional technology configured to form predetermined intersection or ring portions in the lengthwise direction as described above, there is a Korean Patent No. 10-0457629 entitled “Method for Manufacturing Variable State Maintaining Extension Device by Using Shape Memory Alloy and Extension Device Manufactured Using the Same” (hereinafter referred to as the “conventional technology”).
In the case of the above conventional technology, a stent is manufactured by weaving wire according to a predetermined method, with the result that there is manufactured a stent, in which portions in each of which a structure configured such that wire sections intersect each other in the lengthwise direction are disposed and portions in each of which a ring structure configured such that wire sections form a predetermined space in the lengthwise direction are alternately formed.
However, a stent manufactured via the conventional technology cannot provide sufficient stress and resisting force in the case where force is applied from both ends of the stent to the center of the stent due to external force imposed on the placed stent or due to the movement of a region where the stent has been placed after the stent has been placed in order to restore a stenosed region. Accordingly, the stent has the problem of being bent or dislodged from the location where the stent has been placed.
Furthermore, a stent manufactured via the conventional technology is problematic in that metallic fatigue imposed on the wire of the stent increases due to contact between wire structures and due to the twisting of wire structures attributable to the bending of the stent, thus resulting in a reduction in the life span of the wire.